Cordierite Hornfels thin section microscope slide exhibiting a dark colour and a characteristic none crystalline form. Fine grains fit together like the fragments of a mosaic, this is often referred to as rough pavement or pavement structure. Larger crystals of cordierite can be seen scattered throughout the fine matrix. Cordierite is a common component of hornfels produced by the contact metamorphism of pelitic rocks. Shales, slates and clays are metamorphosed to yield biotite hornfels represented by these particular thin sections. The samples from which the thin sections were cut was collected near Carrock Fell, Cumbria. Each section is made to 30 microns thickness and the glass is 46 x 27 mm in size with a cover slip. Supplied in a protective card sleeve with a label, ideal for microscopy and educational purposes.